The Design And Application Of Functional Styrene Series Thermoplastic Elastomer

In recent years,poly(styrene-b-isoprene-b-styrene)(SIS)-based hot-melt pressuresensitive adhesives(HMPSAs)have received considerable attention in transdermal drug delivery systems(TDDS)due to their unique properties,convenience and environmentally friendly features.TDDS mainly consists of drugs,liners,adhesives,permeation enhancers and backing layer,among which SIS-based HMPSAs not only serve as a carrier of drugs but also adhere TDDS to the skin for systemic delivery of the drugs.SIS-based HMPSAs mainly consist of SIS copolymers,tackifier and plasticizer,are non-polar in nature so that they are mostly utilized in administrating lipophilic drugs,which greatly restrict their application for transdermal drug delivery systems.Therefore,it is necessary to increase the polarity to prepare a novel kind of HMPSAs suitable for hydrophilic drugs.The main work was carried out in the work as follow:(1)Synthesized functionalized SIS graft copolymers SIS-g-PI with well-defined molecular structure via the combination of in situ peroxidation,anionic polymerization and graft-onto reaction,their structures were characterized with 1H-NMR and GPC.Developed SIS-g-PI based HMPSAs used functionalized SIS-g-PI as skeleton polymer,the compatibility,adhesion properties and drug release properties of SIS-g-PI based HMPSAs were studied.It was found that the epoxide groups could provide release channels to hydrophilic drugs even though they badly damage the adhesive performances of HMPSAs due to their weak miscibility with tackifier resins.However,the PI branches could effectively improve the compatibility between the main chains and tackifier resins and impart good adhesive performances to the SIS-g-PI based HMPSAs.(2)Functionalized SIS copolymers with polyethylene glycol(PEG)block were synthesized by a anionic polymerization approach,their structures were characterized with 1H-NMR 、 FT-IR 、 GPC and DSC.They were used as skeleton polymer to develop functionalized SISG-based HMPSAs.Their adhesive performance and in vitro drug release behavior were measured.The results displayed that the introduction of functional PEG block could enhance the polarity of SIS copolymers.Functionalized SISG-based HMPSAs showed good adhesive performance and in vitro release behavior of hydrophilic drugs.